Drawing instrument



Feb. 2, 1960 G. s. DOLGORUKOV DRAWING INSTRUMENT Filed Dec. 51. 1953 J in INVENTOR.

DRAWHJ- INSTRUMENT Gregory S. Dolgorukov, Ferndale, Mich.

Application December 31, 1953, Serial No. 401,596 I .4 Claims. c1. 33-112 V This invention relates to drawing instruments and more particularly to an improved T-square, with the aid. of which the user can make drawings without the necessity of having a drawing board, mounting paper thereon and dismounting the same.

Most of industrial drafting is done on drawing tables on which large sheets of drawing paper may be mounted. However, a very large portion of drawings in schools, ofiices and homes has to be done on relatively small sheets of paper and, therefore, is done on small drawing boards adapted to receive smaller sheets of paper; For working on such a drawing board one has to have substantially the same equipment as working on larger boards except for size with respect to some of the equipment. For instance, smaller T-squares are available for use on smaller drawing boards or drawing boards with sliding straight edge strung to the board for drawing parallel lines are used. Small drawing boards come in various sizes, the smallest board in common use being approximately 14 x 20 in size. A T-square for use with such a drawing board is made to overhang the board by approximately 1 to 3 inches and is, therefore, approximately 21 to 23 inches long from the guiding edge of the head to the end of the ruler. An exceedingly large number of various drawing boards with devices to draw parallel lines thereon have been developed and are on the market.

However, use of all such drawing boards and T-squares has a serious disadvantage making their use most inconvenient under many conditions, particularly for making an occasional drawing such as an engineer, an executive or other persons working at a desk may need as an'enclosure to a letter, etc.

In the first place, in addition 'to the drawing board and the T-square, the user must have available drawing paper usually sold in larger sheets or in rolls, thumb tacks or adhesive tape, and he may have to cut such paper to sheets or proper size which may be rather inconvenient or annoying to do at the office desk. In addition, the drawing board must be stored in a proper place. There is usually no room for it either on the top of an executives desk or in the drawers thereof which are relatively small or shallow and are usually crowded with other articles. 'Moreover, when a desk engineer or a person in similar situation has to make a drawing he has to mount the paper on the drawing board with the use of the thumb tacks or adhesive tape. If the drawing is not ited States Patent completed and it is not desirable to leave it in the open,-

desk in the office has been considered somewhat of a nuisance.

The same difficulty prevails in homes where a drawing board placed on an edge against the'wall in a room or in the closet or. left on a desk or dining room table may be in the way. Keeping and using a drawing board at home is often very inconvenient.

One of the objects of the present invention is to provide an improveddrafting instrument, whereby the above difficulties and disadvantages are eliminated, and small drawings can be easily and quickly made with the same degree of perfection as on the drawing board but without the necessity of using the same, as well as without the necessity of mounting'and dismounting the drawing paper.

Another object of the present invention is to provide a drawing instrument of the foregoing nature whereby making drawings at a desk including an executives desk, chief engineers desk, drawing room supervisor, etc., does not crowd the desk or present undesired appearance. A person such as a chief draftsman that has been taken oflf the board and has been given a desk, isusuallynot readily willing to go to a drawing board for making a sketch ora small chart; he worked too many years for his promotion to beseen again working on the board and perhaps left there.

Another object of the present invention is to provide a drafting instrument particularly advantageous for use of an executive engineer, sales engineer, and others who workat desks andfor whom going to a drawing table or keeping at the ofiice' desk a drawing. board with a standard ,Tesquareythur'nb tacks, etc., for an occasional small drawing is inconvenient, crowds the desk and the desk drawers. 1 V

A further object of the present invention is to provide an improved drawing instrument whereby a partly comjpleted drawing, that has to be put away inorder to start a new drawing or several of them, need not be dismounted and mounted again and whereby work may go substantially simultaneously on a number of such drawings. V

A still further object of the present invention is to provide an improved drawing instrument whereby various office forms, such asthose used in accounting, can be easily and quickly made on'plain paper and ruled vertically and horizontally not only to provide the vertical graphs but also lines for writing.

A still further object of the present invention is to provide an improved drawing instrument, the use of which permits leaving of the unfinished drawing on the desk or putting them away into drawers without presenting undesired appearance on the desk or crowding the desk drawers.

A still further object ofthe present invention is to provide an improved drawing instrument which can be carried around in a brief case or. with books as by students and used in classes, in field work, and. while traveling.

' A still further object of the present invention is toprovide an improved drawing instrument which is very advantageous in ofiice use when making advertising layouts, various accounting forms, plans and diagramsand in working athome, and which enables the user ,to draw lines at various angles without drafting triangles.

A still furtherobjectof the present invention is to provide an improved drawing instrument, particularly a T-square with the aidfof which measurements can be taken not only along the, ruler thereof but also in the direction perpendicular thereto.

A still further object of the present invention'is to provide an improved T-s quare with the use of which drawings can bemade directly on a pad of paper without using a drawing board, with the pad being usable until only a few sheets are left thereon without awkward operation of the instruments.

A still further object of the present invention is to provide an improved T-square in which measurements along the ruler or the blade are made without interference from the head.

A still further object of the present invention is to prd vide an improved T-square which does notrock on its guiding edge on the head and in which the bearing surface of the guiding edge on the head, in spite of the very small thickness thereof, is not impaired.

It is an added object of the present invention to provide an improved drawing instrument of the above nature which is simple in construction, dependable and convenient in use, produces work of precise nature, and is relatively inexpensive to manufacture.

Further objects and advantages of this invention will be apparent from the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification, wherein like reference characters designate corresponding parts in the several views.

Fig. 1 is a perspective view showing my improved drawing instrument in use.

Fig. 2 is a top view of my improved drafting instrument.

Fig. 3 is a sectional view taken in the direction of the arrows on the section plane passing through the line 33 of Fig. 2.

Fig. 4 is a fragmentary view of a T-square including a plurality of ruling or measuring lines on the head thereof.

Fig. 5 is a view similar to part in Fig. 4 and showing a T-square with scales provided along the guiding edge of the head both above and below the guiding edges of the ruler.

Fig. 6 is a view showing measuring scale provided on the ruler along the lower edge of the ruler, together with a set of angle lines and requiring turning the T-square over for use of the scale and the angle lines.

It is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also it is to be understood that the phraseology and terminology employed herein is for the purpose of description and not of limitation.

In accordance with the invention I discard the former practice of providing a draftsman with a drawing board, drawing paper with means for mounting it on the board, and a T-square. I provide a draftsman with a standard pad of paper from which sheets of paper can be torn one by one, and a T -square having the effective length of the blade, i.e., length from the guiding edge of the head to the free end of the blade, from fl f'to /1 smaller than the larger dimension of the sheet after the same is torn out from the pad. The T-square is used directly against the edge of the pad thus eliminating the necessity of mounting the paper. The user makes the drawingand simply tears the sheets off as the drawings are completed. Therefore, no drawing board, thumb tacks or tape or mounting the paper is necessary. If the user needs to start another drawing or several of them before the first drawing is completed, he merely folds up the sheet with the unfinished drawing and works on the next sheet. Tearing out such next sheet does not affect connection of the upper sheet to the pad. Preserving the pad cover or the top sheet thereof, theuser can fold it down to cover unfinished work. These are distinct advantages over the use of a drawing board.

The head, of the T-square is maderelatively thin such as and, therefore, it bears on the edge of the pad until virtuallyall sheets thereof are used up. In order to' effect tight fit of the guiding edge of the T-square against the edge of the paper, the head of the T-square is recessed or chamfered under the blade to prevent pieces of dirt or other particles such as cement or glue to lodge in the corner and cause rocking of the T-square on the edge of the pad and improper drawings. In accordance with the invention there is provided on the head at least one marking line at a predetermined distance from the guiding edge of the ruler in order to enable the user to line up paper at even distances. This expedient is particularly adavntageous in making up various accounting forms. More than one line can be provided, and such lines may be provided both above the upper edge and the lower edge of the blade.

As a modification, instead of lines, complete scales may be provided on the head with their zero point being at the respective edges of the T-square. In addition, a scale may also be provided on the T-square blade. However, in accordance with the invention such a scale is provided along the lower guiding edge of the T-square and is intended for use when the T-square is turned over, in order to eliminate interference of the head in measuring distances. With scales provided on the T-square blade in a manner to use such scales without turning the T-square over, the scale contacts the paper only at one of its ends, since the head of the T-square raises the po'rtion of the blade adjacent to the head away from the paper. Moreover, using a scale edge as a guiding edge is somewhat confusing and inconvenient due to indentations usually present thereon. Angular lines are provided on the blade whereby various angles may be laid off with the aid of the T-square, thus eliminating the need for drafting triangles or compass.

Referring to the drawings, there are shown therein, by way of example, T-squares embodying the preesnt invention. Referring specifically to Figs. 1-3, Fig. 1 shows a drawing set comprising a pack or pad 10 of rectangular sheet of drafting paper cut to uniform size, stacked and connected together along one of their short edges to form such a pad. Connecting the sheets into a pad may be done by gluing, with or without fabric reinforcement; sewing or stapling near the edge and perforating to permit easy tearing of the sheets, or in any other suitable manner. With such constructions separate sheets may be removed from the pad one by one either from the top or from the middle without affecting connection of the remaining sheets.

It is of importance in connection with the present invention that the larger dimension of the sheets as removed bears a predetermined relationship to the length of the blade or ruler 11 of the T-square. I prefer to have the sheets of the pad to be from to larger than the length of the blade measured from the guiding edge 12 of the T-square head 13 to the free end 14 of said blade 11. Making the blade longer than specified above causes its end to ride over the raised, rugged ridge 15 formed by the remaining glue or the sewing or binding seam, as the sheets are removed, and makes the use of the T-square on the pad highly unpleasant and virtually impracticable, and will thus defeat the combination. On the other hand, making the eifective length of the blade shorter than less than the longer dimensio'n of the sheets as removed, will greatly decrease utility of the combination, since long lines parallel to the long edge of the sheet cannot be brought sufficiently close to the short edge thereof, such as is required in drawing a frame along edges of the sheet o'r making up an accounting form, and thus make the use of such T-square and pad combinationless advantageous.

me-rsquare'comprises the blade 11 and the head 13 cemented or otherwise secured to one end of the blade 11 at rightangles' thereto. The head and the blade may be made of any' suitable material, such as wood, plastic,

metal, or any" combination thereof. They may be opaque, translucent, or transparent, or one of them may be trans- 5. parent and the otheropaque; or one may be translucent and the other opaque, or one maybe'translucent and the other transparent. Moreover, the blade may be made opaque with transparent ruling edges of approximately A" wide; such construction maybe produced by using two different materials,one transparent and the other opaque or translucent; also a:transparent blade maybe opaqued along its middle portion by application of a suitable paint, lacquer, or sheet material; 1

In accordance with the present invention the thickness of the head is made approximately or even thinner, such as 5 This feature is important, since with ahead of 7 or thick, as in conventional .T-squares, only the top portion of the pad of paper can be conveniently used; after such top portion is used up, and the pad becomes thinner, the bottom surface of the head will rest on the table and will separate theblade portion adjacent the head from the paper. With the thickness of the head as specified above, the pad maybe used virtually to its end.

The guiding edge 12-of the head 13 is made straight and is preferably sanded to ensure that no raised spots, such as flash line of plastic molding and similar defects hardly noticeable by eye, are present. The middle portion of the head 13 along the top of the guiding edge 12 is recessed or chamfered as at 16, to approximately half of the thickness of the head or more, with the ends of the chamfer extending beyondthe guiding edges 17 and 18 of the blade for /s,,- A.'.. .Theabovefeature ensures tight fit of the T-square against the edge of the .pad preventing shaky blade producing non-parallelulinesand poor drawing with incorrect geometric constructions. I have found that suchundesirable operation of theT-square often occurs in new T-squares or develops after a 'F-square had been in use for some time. I traced it to some fo'reign particles, such as pieces of dirt, small balls of glue or plastic cement, lodging themselves under the blade in the corner between the blade and the head. A small particle of $4 in size may produce rocking of the blade at its end as much as hi and even more. In my improved T-square due to the provision .of the chamfer 16, such particles do not aifect operation of the T-square.

It should be appreciated that since the charnfer does not extend to the ends of the edge 12, the bearing of the relatively thin edge 12 on the paper is not affected. Since thickness of the edge 12 is limited by the considerations explained above, this feature is ofimportance, since extending the chamfer to the ends of the edge 12 would cause rising of the paper on theedge' and imperfect hearing. Moreover, it would interfere with the use of scales or lines provided on the head of the T-square for the purposes explained above.

In accordance with the invention, I provide at least one line on the head of the T-square along the guiding edge thereof and at a predetermined distance from the upper edge 17 of the blade 11. Said distance is preferably the distance between the lines of ruled paper, such as about A"; and, if only one line is provided on the head, such as the line 20 in the T-square of Figs. 1-3, it is preferable to have it at such distance from edge 17. This line is used for ruling the paper, such as in making up accounting forms. The first line is drawn against the edge 17 of the ruler. Thereu pon the T-square is moved down until the line 20 on the head 13 coincides with the firstv drawn line on the paper. The second line is then drawn against the edge 17, and the T-square is moved down again, and so on until, lining of the entire sheet or a desired portion thereof is completed. If a line similar to line 20 is provided also below the lower edge 13 of the ruler and at the same distance therefrom, ruling of the paper may be done moving the T-square upwardly. If the head 13 of the T-square is on the right-hand side of the pad, as may be used by left-handed persons, di-

A set of 7 lines 21 -27 is provided on the blade 11 at 30, 45, 60, and to the edges 17 and 18. With the use of such lines, lines may be drawn on the paper at such angles to any given line. I prefer to provide such lines on the upper surface of the blade 11 and to mark degrees of the angles by figures in reverse and upside down as shown in Fig. 2. With such a construction for using these lines the T-square is turned over to have the upper surface of the blade 11 lie, flat against the paper along the entire length of the blade. It can now be seen that when the line 21 is placed to coincide with any given line on the paper, a line at 30 angle to such given line may be drawn against the edge 17 or 18; For drawing a line at a 30 angle to the same given line but pointing in opposite direction, the line 24 is used or the T-square is turned over. The lines 24, 25 and 26 may be-eliminated, if inconvenience of turning the T-squareover is not considered objectionable. In such a case, one set of the three lines should be provided closer to the free end 14 of the blade to decrease interference of the head 13 raising the portion of the ruler 11 adjacent thereto from the paper. With the provision of lines such as 2127, the blade 11 mustv be transparent in order to permit using such lines properly.

Fig. 4 illustrates a T-square embodying the present invention, in which instead of only one line such as 20, two sets 30 and 31 are provided on the head at the same distances from the guiding edges 17 and 18 of the blade, respectively. With such a construction I prefer to have two longer lines at about distance from their respective edges, with two or three short lines at ,5 intervals provided on both sides of each of the longer lines. Such a construction enables the user to rule the paper with closer or wider spacing of the lines, as desired.

Fig. 5 illustrates a T-square which in other respects may be similar to the T-square of Figs. 1-3, but in which instead o-f one line 20, there are provided two scales 3-5 and 36, each having its starting or zero point at a line drawn along theedges 17 and 18, respectively. With such a construction, distances may be laid out or measured from lines drawn along the edges 17 and 18'.

Fig. 6 illustrates a T -square which in other respects may be similar to the T-squares of Figs. 1-5, but in which a scale is provided on the blade in a manner explained below. In accordance with the invention, I discard the formed practice of providing the scale on the top surface of the blade with the zero or starting point thereof being at the guiding edge of the head. With such a construction measuring of distances could be properly done using only the portion of the scale near the free end of the blade. It should be appreciated that for measuring distances the T-square may have to be taken off the guiding edge of the board and placed to have both its ruler and head on the paper. The portion of scale adjacent the head, being raised from the paper by the head for the thickness thereof, such as A or more, is thus made virtually useless for measuring. In accordance with the invention, the scale, such as 37, is provided in a manner to use the ruler 11 with its upper surface lla of the blade being flat against the paper throughout its entire length, i.e., with the T-square being turned over. In accordance with the invention the scale 37 is provided along the lower guiding edge 18 of the blade 11, which edge becomes the top edge when the T-square is turned over, as shown in Fig. 6. With such a construction, the upper guiding edge 17 of the blade 11 is plain, and has no scale interfering with its guiding function in the use of the T-square for drawing lines along its edge 17. It should be appreciated that presence of a scale on a guiding edge is somewhat confusing and it usually produces indentations on an edge which should be perfectly smooth.

For use of my improved scale, the T-square is turned over, and the surface 11a of its blade is made to lie flat on the paper without interference from the head 13. It

printing may be done on the upper surface 11a of the blade 11, but the printingin' such a case be done in reverse and upside down'in' order to indicate to the user that the T-square should be turned over for use of the scale. In accordance with the invention, the zero point of the scale may be either at the edge 12 of the head or at a distance therefrom.

Witha T-square intended to be used in combination with a standard pad of paper 8 /2" x 11'', I prefer to provide a 6 scale with the zero point at approximately 3' inches from the edge 12, with the set of angle lines, such as lines 21-27 of the construction of Fig. 2-, being provided between the'zero' point of the scale and the head 13 of the scale. Such an arrangement is shown in Fig. 6. It will be understood, however, that providing angular lines near the end of the ruler, and a scale closer to the head may also be advantageous under certain conditions. ing of the scale and of the angle lines is preferably done on the upper surface 11a of the blade in reverse and up side down (see Fig. 2 for example) in order to have such printing next to the paper and figures in correct positions for reading when the T-square is turned over, thus avoiding in use confusing shadows from the printing. In Fig. 6, the scale and the angle lines are shown in full lines as they appear to the user. It will be understood that actually the printing is seen through the thickness of the transparent blade 11.

By virtue of the disclosed construction, the objects of the invention listed above and numerous additional advantages are attained.

I claim:

1. A drafting T-square comprising a head made of a plastic material and having a guiding edge, and a' blade cemented to said head; said head having thickness of not less than and not more than and provided with a chamfering recess along the top of said guiding edge under said blade to approximately one-half of the thickness of the head, said recess extending beyond the two edges of the blade but terminating at a substantial distance before the ends of the head.

2. A T-square adapted to be used without a drawing board and directly against the edge of a pad of paper to bear directly on the edge of the drawing sheet, said T-square comprising a head of approximately /si" in thickness and a blade on said head at the right angles thereto and having the length from the head to its free end from 10% to 10 at least one line provided on With both of such arrangements, actual print- 8, said head at a distance ofapproximately from the guiding edge of the: blade, and a chamfer recess provided on the head along the 'guiding edge thereof under the blade, the depth of said' recess being less than the thickness of the head under'the blade, said recess extending from under the ruler on both sides thereof, but terminating at a substantial distance from the ends of the head;

3. A drafting T-squ-are comprising a' head made of a plastic material and having a guiding edge, and a blade having one end secured to' said head at rightangles thereto, said head having thickne'ss'of approximately Ma" and being angularly recessed along the top of its guiding edge under'the blade, with said recess being less than the thickness of the'head under the blade and terminating before reaching 'theends of the head, and at least one marking line provided on the head beyond the end of said recess at a predetermined distance from the edge of theblade.

4. A drafting T-square defined in claim 3 with its blade References Cited in the file of this patent UNITED STATES PATENTS 563,465 'Farley July 7, 1896' 818,051 Ross Apr. 17, 1906 994,570 Castillo June 6, 1911 1,046,365 Allin Dec. 3, 1912 1,053,083 Bli'zard et' al Feb. 11, 1913 1,154,673 Van Ness' Sept. 28, 1915 1,376,098 Jones Apr. 26, 1921 1,488,401- McCracken Mar. 25, 1924 1,599,776 Lazarevich Sept. 14, 1926 1,713,025 Castlemen May 14, 1929 2,000,247 Niukkanen et a1 May 7, 1935 2,373,338 Rakauskas Apr. 10, 1945 2,393,228 Blitz Jan. 22, 1946 2,469,672 Wartinen May 10, 1949 2,588,079 Boehm Mar. 4, 1952 FOREIGN PATENTS 29,530 England "Dec. 23, 1896 117,137 Germany Mar. 6, 1900 908,490 France Apr. 10,- 1946 l26,838 Switzerland July 2, 1928 

